The classroom was empty now, only Arthur sat there on his desk thinking of what he should do. After a while, he looked at the hues of orange the sun has cast over their academy's yard. Students were using their abilities to their heart content, training together, and preparing for the national exam. Others were honing their minds, aiming for any field of magical engineering they could obtain.

A breeze tickled his face, refreshing his thoughts. He stood up and left the empty classroom toward the library to read about essences. After asking for some direction from students rushing to do their club activities, Arthur reached the library.

It was a separate building beside their classes, emitting an ambiance of antiquity with the decorated walls and statues. Students came in and out, some taking books and others returning them.

The interior was just as classical, making Arthur marvel at the beauty of its simplicity. A library clerk sitting behind her desk, rows of bookshelves on the sides, and tables in the middle with a small café the students could order from.

"Hello, where do I search for a book?" Arthur walked over to the library clerk, placing his arm on the counter. The clerk looked at his arm before pushing it away. She took out a towel and some sort of cleaner as she began to 'cleanse' the place Arthur placed his arm on.

"You can pick a booklet from over there; each section of the library is mentioned there. If you don't understand something, please ask." The girl didn't mention anything about Arthur's arm like it never happened, and she started giving instructions before going back to her book.

Picking up a booklet, Arthur started reading it. He didn't mind the clerk's attitude since everyone had their unique traits. He searched for any related topics, finding two sections called "Awakening and Abilities" and "Mana's Properties" that he memorized their number in his mind. He placed the booklet and headed toward the Awakening and Abilities section, skimming through the titles.

'These are mostly about how to awaken, guides to awakening, and records of abilities and how to train them. I don't think there's anything about essences here.' Arthur left the section and went to the other one, also skimming through the titles as he walked.

After reading them for a while, he found several books that might have what he looked for. However, many of them lacked any advanced knowledge. He looked again before finding a thick book called 'Evolution of Mana' that piqued his interest, even if it wasn't related to what he looked for.

Arthur took the book and went toward the tables. Unfortunately, all of them were occupied by students and their friends since the exams were so near. The theory was less exciting than abilities and hunting, but its jobs paid well without any risks.

Since this academy focused on awakeners, most students here didn't want to go to normal jobs like doctors or engineers. They wanted to specialize in the more magic related fields since that would give them an exciting major in college plus being a lot more profitable.

Arthur looked at the taken tables before finding a table with a single student. The student looked to be a girl from her hair and uniform. However, she was sleeping on the book. Arthur looked at the girl with a bob-cut hair almost drooling over the books and didn't know what to make of it.

In the end, Arthur used his camouflage skill to decrease the noises he made and sat on the opposite end of the table. The girl didn't wake up and Arthur sat down to read his book quietly.

The book described mana in general, its history, etiology, its role in the world and the human body, and its properties like mana resonance, mana waves, and any other properties of this energy. It was a fun read, as Arthur learned a lot of things from it. However, he needed to leave the finer reading later since he needed to understand the essences.

Referring to the index, he found a chapter titled Quintessence and Essences. He flipped the pages until he reached the beginning of the chapter where the author began to narrate some historical facts.

"Dungeons appeared three hundred years ago, and that's a fact. However, their emergence doesn't correlate in any way to mana. Mana existed since ancient times since it was the energy of life. However, humans had less control over it, with only a select few families hidden from the world being able to use it.

"After dungeons appeared, our world's mana increased at an alarming rate. Monsters and plants started evolving, and so did humans. Ability users were now a common thing, and monsters began to drop their essence in the form of skills. The time before this, skills were only inherent – heroic tales documented by some ancient scriptures – in a few individuals.

"This raises a question, what is an essence? The studies made over the years revealed the outline of this concept, not the finer details. However, we first need to understand the basic concept. The evolution of mana."

"The Yalveran Union appeared 300 hundred years ago, a unification of three kingdoms that faced the threat of dungeons and monsters." The girl sitting close to Arthur muttered, and the latter had to turn his focus away from the book. As he looked at her, he found her to be still asleep.

'Is she dream-talking? She must have overworked herself.'

Arthur ignored the girl and resumed his reading. The author of this book had a unique way of writing that drew his attention even if he didn't want to.

"An experiment done by a magic engineer name Hassan Alrami two hundred years ago showed results that shocked the world. Hassan worked in a potion lab, using mana to create medicine that surpassed the normal drugs used. He wanted to create a mana potion that would be crowned as a Dragon Leap, creating dragons from men by giving them extraordinary amounts of mana.

"In the end, his project failed and such a potion was never created. However, like most discoveries, he found something far more interesting by accident. The condensation of mana caused it to evolve in quality, creating – what we now call it – a mana essence.

"It was then that many started using this method to create a mana essence, advancing magic engineering by leaps and bound. Mana essence explained a lot of things we didn't know the reason for, like mana cores and how humans were able to evolve further.

"Mana cores were the manifestation of mana essence in monsters, only differing in their quality. The evolution of monsters and the way monsters evolved – by eating the flesh of other creatures – made us unable to use the mana cores as essence.

"With the realization of its existence, extensive research went into mana essences in humans. They were able to establish a systematic way to rise from rei-rank to Vetus-rank, unlike the undeveloped methods used in the past. They also discovered the difference between people's mana essence, giving their mana different properties. People with green essence could use green mana, specialized in healing and life-energy. Red essence was a sign of instability and amplification, used mainly by berserks. From this, the existence of quintessence came into the world.

"Quintessence." The girl opened her eyes next to him, standing up from the seat and gazed at Arthur. "The difference between a rei-ranker and a Vetus-ranker. Boosting their abilities further and allowing them to evolve." She recited as if she was reading a book. Arthur looked at her, scared out of his wits.

"How did you know I was reading?" Arthur felt like his thoughts were invaded, fearing it was another mind-reading ability.

"Quintessence depends on each person and their mana. People with red mana would develop a red quintessence. The main function of the quintessence is to supply mana to the relevant skills. If a berserker can make his quintessence, then skills with amplifications or similar traits would be a lot easier to use."

"Seriously, dude, you're creeping me out." Arthur closed his book as he stood up from his seat, deciding to take the book home. He left the library under the eyes of the creepy girl he just met.

He got home using the train and told his brother that the issue has been taken care of. Seeing his brother safe and unharmed, Oren sighed in relief. Arthur took the book back to his room before continuing to read.

The rest of the things Arthur read were as the bob-cut girl said, talking about each person having different types of mana and their properties. It also explained that there were some disadvantages to the difference in mana, as healers would pay enormous amounts of mana to use the skills of a berserk. This has established boundaries between skills, as people wouldn't learn the skills that would be disadvantageous.

Arthur read that most people had blue mana because the human body was composed of 70% of water. Luckily, they can change the properties of their mana through some training, potions, and rituals before reaching the Vetus-rank.

"Does that mean I can use different types of mana by absorbing their essence?" Arthur wondered, unsure of the results.

Arthur remembered the skill he last obtained from the underground tunnel, called Shadow Swap. It had a five meters radius but it consumed a lot of mana. With a thought, Arthur used the skill and appeared on the other corner of his room.

This skill used to consume 10 points of mana before, a sixth of Arthur's total mana. This was the reason skills were unfavored in the lower ranks since people would have less mana than the upper ones. It seemed that wasn't the only reason, as people above the Vetus-rank could use their quintessence to reduce the cost of mana.

The skill Shadow Swap consumed only 8 points of mana after absorbing the dark essence. So even though Arthur had yet to reach Vetus-rank, his mana consumption would still change.

The only worrying factor was if it was possible to have more than one essence per person, and Arthur would have to look into the matter more.